This program project remains directed toward acquiring a better understanding of the molecular organization of cell membranes and of synaptic structures. Several specific highly organized membranes in situ and in isolation will be studies by multiple electron microscopic (EM), x-ray diffraction and biochemical methods. The most highly ordered ones along with catalase as a test object and model membranes will be studied by the low beam EM methods of Unwin and Henderson at 25 degrees C - 150 degrees C and less than 5 degrees K. Two major limitations of the freeze-fracture-etch technique will be attacked by the development of better specimen freezing methods and a higher resolution (3-5 A) metallic replication technique. Model systems of multilayers of lipids and proteins will be prepared by lifting monolayers from a Langmuir trough successively onto Epon substrates and studied by EM and x-ray diffraction techniques. These studies will be correlated with studies of the properties of black lipid films and of bilayer vesicles. Studies of Octopus brain will be continued with the aim of better understanding the organization of neuropils that are involved in learning. An effort will be made to establish whether or not specific morphological features unique to the learning neuropil exist. Another aspect of the program aims at a better understanding of the mechanism of assembly of microtubules and of the structural organization of alpha proteins. These latter studies will be done by x-ray diffraction, EM and biochemical techniques. Studies of the molecular organization of gap junctions (synaptic disks) isolated from liver and ovarian granulosa cells will be carried out by a combined biochemical, electron microscopic and x-ray diffraction approach. Studies of intercellular contact regions including gap junctions in ovarian Graffian follicles will be pursued. This work will include the mapping of specific hormone receptors in the surfaces of ovarian cells. Studies of the structure of retinal rod outer segments aimed at elucidating the mechanism of action of rhodopsin will be pursued as will studies of the Halobacterium purple membrane. Studies of AcCh receptors in torpedo electroplax membranes will be pursued.